(1) Field of the Invention
The present invention relates to test data processing and in particular, to a test data processing system and method for calibrating and post-processing acoustic and non-acoustic test data and for plotting the acoustic and non-acoustic test data.
(2) Description of the Prior Art
Turbine Pump Ejection Systems (TPES) are used on U.S. and foreign submarines for launching devices from horizontal launch tubes. These systems are generally tested in a manufactured or refurbished condition at a test facility, such as a Submerged Launch System Test Facility (SLSTF) or a Submerged Torpedo Tube Test Facility (STTTF) such as those operated by the Naval Undersea Warfare Center Division, Newport. In one example, numerous pressure transducers and accelerometers are mounted at predetermined locations on a pump being tested and in the test facility for sensing acoustic and non-acoustic conditions during launching.
Conventional systems and methods for analyzing test data are tedious and imprecise. During a number of launchings, the signals from the transducers are traditionally recorded on a twenty-eight track analog tape recorder, and the data played back through a strip chart recorder. Measuring the maximum value for each signal trace requires manually measuring the printed signals with a calibrated scale. These maximum values are then manually entered on predefined baseline plots.
This manual process of analyzing test data with existing strip chart recorder based systems has a number of disadvantages. Manually determining peak data values from strip charts with a calibrated scale and manually plotting the results is laborious and time consuming. The measuring and recording of the signal values are also subject to human error and are often inconsistent when taken and read by different individuals. The errors could be further compounded when misread or misinterpreted data is incorrectly plotted in test documentation.
Accordingly, one object of the present invention is to provide a system and method for data collection, reduction and post processing that is fully automated.
A further object of the present invention is to provide a system and method for processing test data that minimizes human error and inconsistencies while significantly speeding up data analysis.
Another object of the present invention is to automatically generate a signal-time history and baseline plots of peak values to provide a quick, accurate, and consistent evaluation of overall performance of the system being tested.
A further object of the present invention is to provide a system and method for processing test data in a user friendly computer environment, for example, on an existing personal computer (PC) system in a xe2x80x9cWindowsxe2x80x9d-based environment.
The present invention features a software package operating with off the shelf hardware for processing data acquired from a test facility having a plurality of sensors such as transducers and accelerometers. The test data processing system is preferably in the form of software running on a PC in a windows-based environment. According to one embodiment, the test data processing system is used with a data acquisition system having a data acquisition board configured on a PC. The data acquisition system acquires and stores collected or transducer data and calibration data for processing. The data acquisition system may include a multitrack recorder for recording and saving the data.
The processing system consists of various software routines which read and reduce the collected data from both acoustic and non-acoustic sensors, and generates several series of plots.
Both non-acoustic and acoustic data processing software read the appropriate data files created via a PC based data acquisition card. The processing software reduces the data from 16-bit binary format to engineering units (e.g. ft/s, psi, etc.) using calibration factors. The data is presented on a series of xe2x80x9cperformancexe2x80x9d and xe2x80x9cacousticxe2x80x9d plots, displaying the sensor signals as a function of time and their corresponding peak values. These peak values (one file for reach sensor), are stored in a series of xe2x80x9cmaxpakxe2x80x9d files. Each xe2x80x9cmaxpakxe2x80x9d file contains the run number, peak turbine inlet pressure and peak sensor value (in engineering units).
A multitude of routines generate envelope plots for both xe2x80x9cperformancexe2x80x9d and xe2x80x9cacousticxe2x80x9d data. Appropriate xe2x80x9cacousticxe2x80x9d and xe2x80x9cperformancexe2x80x9d peak values are read from each xe2x80x9cmaxpakxe2x80x9d file and plotted on a series of baseline curves (one for each sensor). Three xe2x80x9cbaselinexe2x80x9d curves are presented on each plot for each sensor. These curves reflect +/xe2x88x92 two standard deviations and average of peak sensor values plotted against peak turbine inlet pressure taken from representative turbine pumps. These baseline curves represent the anticipated xe2x80x9cperformancexe2x80x9d and xe2x80x9cacousticxe2x80x9d operational xe2x80x9cenvelopexe2x80x9d.